We haven't received an update for 3 weeks now and we all agree that Beta 2 is horrible and makes our devices useless! It's hard to cope with it but I have some temporary solutions that I've been using to limit the frequency of this issue.
The solution is to install Galaxy Max Hz app and to use bixby routines.
Here is a step by step guide:
1) Google "Galaxy Max Hz apk XDA developers"
2) download and install the apk from xda website (its safe)
3) Open the app and give the required permissions then scroll down to the bottom and select "Force Lowest Hz"
Now the next stage is to setup a bixby routine to change the screen refresh rate when pressed and reverse when pressed again. Because of Beta 2, I tend to use 60Hz as my default. So the bixby routine changes the display to 120hz then back to 60hz. Believe me, this helps a lot.
Now add a bixby routine widget to the home screen and whenever your device starts lagging/freezing again, just press that widget 2 times.